1. Field of the Invention
The present invention relates generally to a wireless communications network, and more particularly, to an apparatus and a method for reducing a transmission delay through use of HyperText Transfer Protocol (HTTP) and a processing load of an HTTP server, in a wireless communications network.
2. Description of the Related Art
Wireless communication systems have been developed to provide voice services to users, and have expanded to additionally provide data services. In recent years, wireless communication systems have been further developed in order to provide high-speed data services. However, due resource shortages and user demands for providing a higher speed services, a more-advanced wireless communication system is required.
FIG. 1 illustrates a network structure of a wireless communication technology.
FIG. 1 is a diagram illustrating a communication system in which an Internal Protocol (IP) communication message is transmitted from a mobile communication User Equipment (UE) to a mobile communication that which terminates an IP communication of a corresponding UE.
FIG. 1, depicts as communication network according to a Long Term Evolution (LTE) scheme, which is a 4th Generation communications network, and therefore, a Packet Data Network (PDN) Gateway (PGW) is used in the network. With respect to FIG. 1, all IP message exchanges performed between a UE 110 and other communication devices using an internet connection are performed through a corresponding PGW 120. Thus, when client software based on a HyperText Transfer Protocol (HTTP) is used, all messages of the corresponding HTTP-based services are processed via the PGW 120.
An HTTP proxy device 130 is used between the PGW 120 and an HTTP server 140, thereby substantially providing an HTTP service in order to provide an HTTP service having a more advanced performance than performance provided by the mobile communications network. The HTTP proxy device 130 improves user satisfaction with respect to the HTTP service by generally providing an improvement in transmission speeds by compressing HTTP traffic, security reinforcement by protecting an HTTP user or an HTTP server from illegal or malicious attacks, and caching, which includes storing frequently-accessed contents of the HTTP server and rapidly transferring the stored contents to the HTTP user.
FIG. 2 is a diagram illustrating an internal configuration of a conventional HTTP proxy device.
Referring to FIG. 2, in the HTTP proxy device 130, HTTP clients are connected to one side thereof, and an HTTP server is connected to another side thereof. Since the HTTP proxy device 130 terminates 4-layered communication (e.g. opposite Transmission Control Protocols (TCPs)), a function of matching a left side of FIG. 2 (i.e., communications with respect to the router 210) and a right side of FIG. 2 (i.e., communications with respect to the HTTP server 140) is needed.
To this end, the HTTP proxy device 130 includes a router traffic handler 220 for directing the router 210 to which the HTTP clients are connected, and a server traffic handler 260 for directing the HTTP server 140. The HTTP proxy device 130 further includes an HTTP bearer processor 230 for performing the matching operation. The HTTP bearer processor 230 stores, in an HTTP session database 250, information regarding a 4-layered connection with the HTTP clients 110 and information regarding a 4-layered connection with the HTTP server 140, in order to correctly match the HTTP clients 110 and the HTTP server 140. An HTTP session manager 240, which directs the HTTP bearer processor 230 to match sessions of the HTTP client 110 and the HTTP server 140, operates based on the corresponding information.
Thus, the HTTP session manager 240 performs control operations, such that the HTTP bearer processor 230 correctly matches the sessions of the HTTP client 110 and the HTTP server 140, based on the information of the HTTP session database 250.
Several examples problems of the above-mentioned communication systems are described below.
First, when the HTTP client 110 transmits a plurality of HTTP request messages to the HTTP server 140 through one Transmission Control Protocol (TCP) connection, the HTTP server 140 must transmit HTTP response messages, which are responses to the HTTP request messages, to the HTTP client 110 in the same sequence as the HTTP request messages. However, when generation or transmission of one of the HTTP responses is delayed, transmission of all the following HTTP responses to the HTTP client may be delayed.
Second, one TCP session is maintained for a long time in order to connect the HTTP client 110 and the HTTP server 140 to each other once and then to reconnect the HTTP client 110 and the HTTP server 140 to each other, such as in a Persistent HTTP mode originally defined in the HTTP standard or an SPeeDY (SPDY) recently proposed as an improved alternative. At this time, when the HTTP client 110 is not normally performing TCP connection deactivation with the HTTP server 140, the HTTP client 110 must remove the corresponding TCP session by itself. In this situation, when a TCP connection between the HTTP client 110 and the HTTP server 140 is abnormally terminated due to instability of wireless connection of a UE in the mobile communications network, or when an IP address is changed by performing a handover through moving the UE, the existing TCP connection is abnormally operated, and therefore, it is difficult for the HTTP server 140 to identify the abnormal operation. Even when a user performs cyclic message transmission/reception to/from the HTTP server 140 and the HTTP client 110 to detect abnormal termination, in order to identify movement of the corresponding UE, wireless traffic is wasted. Further, when the TCP connection, in which the HTTP server 140 is abnormally terminated, is maintained for a predetermined time period, an additional processing load of the server is unnecessarily generated.
Third, when one TCP session is maintained for a long time, in order to rapidly reconnect the HTTP client 110 and the HTTP server 140 to each other, such as with Persistent HTTP or SPDY described with respect to second problem above, the corresponding HTTP client 110 is a mobile communication UE, and therefore, when the IP address is changed due to a handover in wireless communication, the HTTP server 140 cannot identify the changed IP address. Therefore, when the base station is changed due to movement of the UE in the mobile communications network, the UE may not use the currently-used IP address and may change the IP address thereof. For example, when an Access Point (AP) is changed in a Wireless Local Area Network (WLAN) or a PGW is changed in a Long Term Evolution (LTE) network, when the IP address of the corresponding UE is changed, the TCP connection between the HTTP server 140 and the HTTP client 110 is abnormally terminated, such that the second problem is generated, and therefore, the IP address allocated to the corresponding UE becomes useless. Further, the communication service that was previously being performed is abnormally terminated due to deactivation of a TCP connection with the UE.
Fourth, in the current art, when one TCP session is maintained for a long time, such that the HTTP server 140 transmits a push message to the HTTP client 110, such as when using Persistent HTTP or SPDY as described with respect to the second and third problems herein above, the UE must consistently maintain the IP and the TCP sessions with respect to the HTTP server 140. In this situation, when there is no information to be transmitted or received by the UE in the mobile communications network, a wireless connection is deactivated and an IP is returned, or when monitoring traffic of the corresponding UE indicates that there is no information to be transmitted or received in the mobile communications network, an IP connection is deactivated. However, when the IP of the UE is deactivated, such as in the above-mentioned case, it is impossible for the HTTP server 140 to perform the HTTP push to the corresponding UE. In order to address above-mentioned problem, the connection may be maintained by cyclically transmitting a message to the UE. However, since a wireless data communication connection of the UE must be maintained in order to maintain the connection, communication costs of the UE and battery usage increase. Further, since the IP is consistently allocated to the corresponding UE, even in the mobile communications network, processing and a memory load for maintaining the corresponding IP session are generated.